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arXiv 1209.0129math.COcs.DM
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排除拓扑子式的一个强结构定理

A stronger structure theorem for excluded topological minors

Zdenek Dvorak

摘要:

Grohe和Marx证明了,如果G不包含H作为拓扑子式,则存在常数g=O(|V(H)|4),D和t仅依赖于H,使得G是至多包含t个度大于大于D的顶点或几乎嵌入至多g的亏格的某个曲面的图的团和.我们加强了这一结果,给出了更精确的描述后一种基本图的分解-我们只允许图(几乎)嵌入的方式是不可能的H(类似于未成年人的结构定理,其中只有图形几乎嵌入在表面中,H不嵌入是允许的)。这使我们能够给图结构的结果,避免固定的图作为一个浸入和有界无穷大的图的容许性。

英文摘要:

Grohe and Marx proved that if G does not contain H as a topological minor, then there exist constants g=O(|V(H)|^4), D and t depending only on H such that G is a clique sum of graphs that either contain at most t vertices of degree greater than D or almost embed in some surface of genus at most g. We strengthen this result, giving a more precise description of the latter kind of basic graphs of the decomposition - we only allow graphs that (almost) embed in ways that are impossible for H (similarly to the structure theorem for minors, where only graphs almost embedded in surfaces in that H does not embed are allowed). This enables us to give structural results for graphs avoiding a fixed graph as an immersion and for graphs with bounded infinity-admissibility.

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